Methods and apparatus for chamber lid cooling

Abstract

A reactor system for use in semiconductor processing, such as for chemical vapor deposition (CVD), atomic layer deposition (ALD), and other deposition steps, that makes use of a reactor module with two or more reaction chambers. The reactor system includes components of a cooling system to provide enhanced temperature uniformity across a chamber lid enclosing the housing or vessel containing the reaction chambers. In part, the cooling system is adapted to utilize convective heat transfer and includes a finned heat sink positioned at the center of the chamber lid in the center space between the external portions of the showerheads of the reaction chambers. Further, the cooling system includes a fan positioned to have its outlet at the center space and over the finned heat sink so that air is directed into the center space and onto the heat sink.

What is claimed is: 
     
         1 . A reactor system adapted for forced convection cooling of a multi-chamber module, comprising:
 a lid for the multi-chamber module;   a set of showerheads supported on the lid, wherein each of the showerheads includes a body with a sidewall extending a distance outward from an outer surface of the lid;   a cooling channel comprising gaps between the sidewalls of adjacent pairs of the showerheads; and   a fan assembly with a fan housing enclosing an impeller and a motor and defining a fan inlet and a fan outlet, wherein, when the motor is operating, cooling air is drawn into the fan inlet from a space exterior to the lid and forced out of the fan outlet into the cooling channel to flow through the gaps.   
     
     
         2 . The system of  claim 1 , wherein the set of showerheads comprises four showerheads, wherein the cooling channel further comprises a center space enclosed by the fan housing, a center portion of the outer surface of the lid, and adjacent portions of the sidewalls of the bodies of the four showerheads, and wherein the fan outlet is configured to direct the cooling air forced out of the fan outlet into the center space. 
     
     
         3 . The system of  claim 2 , further comprising a heat sink positioned within the center space and integrally formed with the lid or in contact with the outer surface of the lid, wherein the heat sink includes a plurality of fins extending outward away from the lid. 
     
     
         4 . The system of  claim 2 , wherein the fan assembly has a center axis that coincides with a center of the center space and a center of the lid. 
     
     
         5 . The system of  claim 1 , further comprising a set of module hardware extending over and at least partially enclosing the gaps, whereby the cooling air is directed to flow between adjacent pairs of the showerheads. 
     
     
         6 . The system of  claim 1 , wherein the motor is a variable speed motor operable over a range of speeds and wherein the system further comprises a controller configured to generate control signals to operate the motor at a first speed and at a second speed higher than the first speed. 
     
     
         7 . The system of  claim 6 , further comprising a temperature sensor adapted to sense a temperature of the lid and wherein the controller generates the control signals to switch between the first and second speeds based on the sensed temperature of the lid. 
     
     
         8 . The system of  claim 6 , wherein the controller generates the control signals to switch between the first and second speeds based on a change in processes performed in the multi-chamber module. 
     
     
         9 . A method of controlling a chamber lid temperature in a reactor system, comprising:
 operating a fan at a first speed to direct a flow of cooling air onto an outer surface of the chamber lid;   sensing a temperature of the chamber lid; and   based on the sensed temperature, operating the fan at a second speed less than or greater than the first speed.   
     
     
         10 . The method of  claim 9 , further comprising processing the sensed temperature with a temperature control band and wherein the operating the fan is performed based on the processing of the sensed temperature. 
     
     
         11 . The method of  claim 9 , wherein the fan is an axial fan and wherein a center axis of the axial fan is perpendicular to the outer surface and coincides with a center of the chamber lid. 
     
     
         12 . The method of  claim 9 , wherein the flow of the cooling air is directed into a center space among four showerheads mounted on the chamber lid. 
     
     
         13 . The method of  claim 12 , wherein the center space includes a heat sink on the chamber lid and wherein the flow of the cooling air is directed through a plurality of fins of the heat sink. 
     
     
         14 . The method of  claim 12 , wherein the flow of the cooling air is directed to flow from the center space through gaps between adjacent pairs of the four showerheads. 
     
     
         15 . A reactor system adapted for cooling a chamber lid of a quad chamber module, comprising:
 the chamber lid;   four showerheads each with a body with a sidewall extending from an outer surface of the chamber lid; and   a fan operable to provide a flow of air transverse to the chamber lid and onto the outer surface within a center space located centrally among the four showerheads.   
     
     
         16 . The system of  claim 15 , further including a fan housing enclosing the fan and the center space, wherein the flow of air is directed from the center space to gaps between the sidewalls of adjacent pairs of the four showerheads. 
     
     
         17 . The system of  claim 15 , further comprising a finned heat sink on the outer surface of the lid within the center space. 
     
     
         18 . The system of  claim 15 , further comprising a controller configured to generate control signals to operate the fan at a first speed and at a second speed higher than the first speed to provide first and second amounts of cooling of the chamber lid with the flow of air. 
     
     
         19 . The system of  claim 18 , further comprising a temperature sensor adapted to sense a temperature of the chamber lid and wherein the controller generates the control signals to switch between the first and second speeds based on the sensed temperature of the lid. 
     
     
         20 . The system of  claim 18 , wherein the controller generates the control signals to switch between the first and second speeds based on a change in processes performed in the quad chamber module.